Braking Feel Simulation System for Hybrid Vehicles

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Solution Overview

Problem

Hybrid vehicles with both internal combustion engines and electric motors face inadequate braking performance from electric regenerative braking systems, particularly at low speeds and when energy recovery is insufficient, necessitating a supplementary hydraulic braking system for effective deceleration.

Innovation Solution

A system that simulates brake feel by using a central control unit to manage the interaction between hydraulic and electric braking systems, including a simulation valve and blocking valve to adjust the braking force feedback to the driver, ensuring a consistent braking sensation through digital or analog control of the simulation valve based on the braking demand.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If electric regenerative braking system is used, then energy recovery is achieved, but braking effectiveness at low speeds and when energy recovery is insufficient becomes inadequate

Engineering Contradiction:
Improveenergy recoveryVSAvoidbraking effectiveness
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent combines electric regenerative braking system and hydraulic braking system into a unified braking system. The control unit coordinates both systems to work together, allowing the hydraulic system to supplement the electric system when regenerative braking is insufficient or at low speeds, ensuring reliable braking performance while maximizing energy recovery.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The simulation valve acts as an intermediary between the hydraulic braking system and the driver. It transmits a simulated braking sensation to the driver's foot on the brake pedal, creating the perception of adequate braking force even when the actual braking force from the electric system is limited, thus maintaining driver confidence and control.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If hydraulic braking system is added to supplement electric braking, then braking effectiveness is improved, but device complexity increases

Engineering Contradiction:
Improvebraking effectivenessVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The simulation valve serves multiple functions: it transmits hydraulic pressure to the driver's foot to create braking sensation, it can be controlled to simulate different levels of braking force, and it works in coordination with both electric and hydraulic braking systems. This multi-functionality reduces the need for separate dedicated components for each function.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The control unit continuously monitors the braking state and adjusts the simulation valve accordingly. It detects when electric braking is insufficient and automatically activates the hydraulic system with appropriate simulation valve control, creating a closed-loop feedback system that manages complexity through intelligent coordination rather than simple additive components.

Inventive Principle:
Principle #23Feedback

3Ease of operation

If simulation valve is controlled to provide braking sensation, then driver feedback is improved, but control complexity increases

Engineering Contradiction:
Improvebraking sensationVSAvoidcontrol complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The control unit uses feedback from braking demand detection and braking state monitoring to automatically adjust the simulation valve. This closed-loop control provides appropriate braking sensation to the driver without requiring complex manual adjustment mechanisms, as the system self-regulates based on real-time conditions.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The braking sensation simulation system is automatically controlled by the control unit based on detected braking conditions. The system serves itself by detecting when simulation is needed and automatically adjusting the simulation valve, eliminating the need for separate control mechanisms or manual intervention for each braking event.

Inventive Principle:
Principle #25Self-service

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The system provides a consistent and effective braking sensation to the driver by simulating the hydraulic braking force even when electric regenerative braking is insufficient, ensuring safe and responsive braking performance across varying conditions.

Implementation Method 1

a conventional braking system in which the brake pedal acts on the hydraulic braking circuit of the wheels

Methodology Applied
Scientific EffectHydraulic pressure transmission: Pascal's Law

Implementation Method 2

use the electric motors for braking by making them operate as electric generators, the braking then being done by energy recovery

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2199163B1Braking feel simulation system and application of such a system.
Publication Date: 2020.01.08 ROBERT BOSCH GMBH
  • EP2199163B1 patent drawingFigure 1~2
  • EP2199163B1 patent drawingFigure 3
  • EP2199163B1 patent drawingFigure 4

AI summary

The system has a cylindrical chamber (20) containing a force transmission fluid (21), and a hydraulic piston (22) sliding in the chamber and driven by a brake pedal (1) and a piston (23) for controlling hydraulic braking circuits (7, 8). The chamber is communicated on a control with a simulation chamber (4) by a simulation valve (3) whose opening rate simulates an effort to the brake pedal. A locking valve (80) operates the braking circuits with the help of muscular energy, and is controlled in a locking state by a central control unit (5), when the simulation system is activated.